Search engines serve to locate information both on the World Wide Web and off. For example, search engines search for documents (or other items) with keywords and return a list of the documents where the keyword was found. Search engines routinely index billions of documents in this manner, which gives users a way to find documents by entering a keyword search query.
However, search engines do not always return the most relevant results in order. A user may enter a search query with a specific intent of the results she wants, but often times the desired documents are not highly ranked. In some instances, this problem stems from the method in which search engines rank documents and the manner in which webpage developers alter their webpages to take advantage of this ranking method. For instance, search engines may rank documents based on the content of the pages (e.g. webpage text) as well as according to anchor texts linking to the documents. Anchor text comprises the visible clickable text in a hyperlink.
When scoring webpages, previous attempts have assumed that the anchor text links between a source site and a destination site are independent from one another, and each individual anchor text link is of equal importance. As a result, these previous attempts assumed that the more incoming links a document has, the more important it is when ranking the document against a search query. This assumption frequently leads to poor search results due to the web developer's ability to effectively game the system.
One such instance where this assumption provides poor search results is in the case of mirror sites. For example poor results occur if two anchor text links come from a single source website or from two identical source web pages on mirror sites. Another instance is when two anchor text links come from two websites having cooperative relationships. These websites are frequently under the control of the same or related users and thusly tend to have a substantial number of the same or similar anchor text links. Yet another instance occurs when anchor text links are purposely created to boost the ranking of the destination page in a web search, as discussed above.
While existing search engine technology has proven very useful, there remains ample room for improvement of search engine technology in regards to adjusting the weight of anchor texts.